#include <math.h>
#include <pango2/pangocairo.h>

#define RADIUS 150
#define N_WORDS 10
#define FONT "Sans Bold 27"

static void
draw_text (cairo_t *cr)
{
  Pango2Layout *layout;
  Pango2Lines *lines;
  Pango2FontDescription *desc;
  int i;

  /* Center coordinates on the middle of the region we are drawing */
  cairo_translate (cr, RADIUS, RADIUS);

  /* Create a Pango2Layout, set the font and text */
  layout = pango2_cairo_create_layout (cr);

  pango2_layout_set_text (layout, "Text", -1);
  desc = pango2_font_description_from_string (FONT);
  pango2_layout_set_font_description (layout, desc);
  pango2_font_description_free (desc);

  /* Draw the layout N_WORDS times in a circle */
  for (i = 0; i < N_WORDS; i++)
    {
      int width, height;
      double angle = (360. * i) / N_WORDS;
      double red;

      cairo_save (cr);

      /* Gradient from red at angle == 60 to blue at angle == 240 */
      red   = (1 + cos ((angle - 60) * G_PI / 180.)) / 2;
      cairo_set_source_rgb (cr, red, 0, 1.0 - red);

      cairo_rotate (cr, angle * G_PI / 180.);

      /* Inform Pango to re-layout the text with the new transformation */
      pango2_cairo_update_layout (cr, layout);

      lines = pango2_layout_get_lines (layout);

      pango2_lines_get_size (lines, &width, &height);
      cairo_move_to (cr, - ((double) width / PANGO2_SCALE) / 2, - RADIUS);
      pango2_cairo_show_layout (cr, layout);

      cairo_restore (cr);
    }

  /* Free the layout object */
  g_object_unref (layout);
}

int
main (int argc, char **argv)
{
  cairo_t *cr;
  char *filename;
  cairo_status_t status;
  cairo_surface_t *surface;

  if (argc != 2)
    {
      g_printerr ("Usage: cairosimple OUTPUT_FILENAME\n");
      return 1;
    }

  filename = argv[1];

  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                        2 * RADIUS, 2 * RADIUS);
  cr = cairo_create (surface);

  cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
  cairo_paint (cr);
  draw_text (cr);
  cairo_destroy (cr);

#ifdef CAIRO_HAS_PNG_FUNCTIONS
  status = cairo_surface_write_to_png (surface, filename);
#else
  status = CAIRO_STATUS_PNG_ERROR; /* Not technically correct, but... */
#endif

  cairo_surface_destroy (surface);

  if (status != CAIRO_STATUS_SUCCESS)
    {
      g_printerr ("Could not save png to '%s'\n", filename);
      return 1;
    }

  return 0;
}